A carbon (C) has been more important as one of next semiconductor materials. For example, a carbon film is used as an antireflection film in a photolithography process, a hard mask in an etching process, an interlayer insulation film with low dielectric constant, a protective film for preventing step punching of a silicon carbide (SiC) wafer, or the like. The carbon film is expected to be used more widely in future.
As a method of forming a carbon film, a plasma CVD method or a thermal CVD method have been suggested.
Also, it has been suggested to added fluorine (F) in a carbon film.
As such, the carbon film, which is used in manufacturing a semiconductor device, is widely applicable in a variety of fields.
However, when a carbon film is formed using the plasma CVD method, although the film forming temperature is suppressed to be low (for example, 100 degrees C. to 500 degrees C.), step coatability may not be good. Accordingly, the carbon film formation using the plasma CVD method is unsuitable for forming a film on an underlayer having concave and convex portion such as a line pattern or a hole pattern.
In addition, when a carbon film is formed using the thermal CVD method, although step coatability is good, the film forming temperature should be high (for example, 800 degrees C. to 1000 degrees C.). Accordingly, the thermal CVD method is unsuitable for forming a carbon film on an upper layer portion of a semiconductor device due to thermal effects, for example, to transistors formed on a silicon wafer.